1. Field of the Invention
The present invention relates to a transport system for green tires between forming and vulcanizing processes in a tire manufacturing installation in which tires are manufactured through a forming process and a vulcanizing process.
2. Description of the Prior Art
In the prior art also, examples in which transportion of green tires between forming and vulcanizing processes was automated (Laid-Open Japanese Patent Specifications Nos. 51-123286 and 51-126275) are known.
With respect to these known examples in the prior art, brief explanation will be made with reference to FIG. 9 which shows a transport system for green tires.
Reference characters a.sub.1, a.sub.2, . . . designate forming machines for respectively forming green tires of different sizes, and storage c.sub.1, c.sub.2, . . . corresponding to the respective forming machines are provided in one end portion of a transport line d.
Green tires carried out from the storage are transported and mounted to respective vulcanizing machines b.sub.1, b.sub.2, . . . provided with press molds of predetermined sizes, by means of transport trucks e.
The above-mentioned operations are controlled by a concentrated controller in which correspondence relations between the respective storage location and particular vulcanizing machines as well as necessary time for transport are preset, and the transport is commenced in response to a transport demand signal issued from a vulcanizing machine.
As described above, in the known example in the prior art, green tires are transported along a looped track from a storage location and to a vulcanizing machine are made to correspond to each other. It is thus, necessary that a vulcanizing time in a vulcanizing machine is synchronized with a time required for carrying out green tires from a storage.
Here it is to be noted that a vulcanizing machine is made to correspond to a storage location, and this is equivalent to that a vulcanizing machine is made to correspond to a forming machine, hence a discrepancy in timing would occur between a forming machine and a vulcanizing machine because their cycle times are generally different, and if the discrepancy becomes large, there occurs an inconvenience in that synchronization cannot be established between the vulcanizing time and the time for carrying out from the storage.
More particularly, if the number of green tires in the storage location become small, then green tires cannot be transported within a required time and so a standby time would occur in the vulcanizing machine. If the storage becomes full, then the forming machine would take a standby state.
In this way, there is a fear that working efficiencies of the vulcanizing machine, the forming machine and the other associated equipment would be greatly lowered.
Such a situation would be liable to occur when a change of production volumes for the respective kinds of tires has arisen, and if this deficiency, is to reduced the number of green tires stored in the storage must be increased, and hence a larger space is required therefor.
Moreover, in view of the general layout, the respective forming machines would be provided with storage equipment, and so generally a large space is necessitated.
In addition, since the track for transporting green tires in the prior art was designed in a structure so as to transport about one or two green tires (in the specification of the prior art, two green tires are transported), in the event that many truck demands issued from the vulcanizing machine side should overlap, the transportation along the same track has a limit, and sometimes a supply of green tire within the required time would be not achieved fully, resulting in a standby state of the vulcanizing machine.
Furthermore, in order to meet the requirement for many kinds of small-amount production caused by diversification of the recent demands, it is necessary to frequently change setting conditions in the forming machines and to frequently replace press molds in the vulcanizing machines, and the timing of the change or replacement is different between the forming machines and the vulcanizing machines. Therefore, with the above-described method for transporting green tires by correlating the storage locations and the vulcanizing machines via a looped track, it is difficult to carry out the transportation so as to meet the requirement with a large flexibility.
Also, since the track must be provided between the forming station and the vulcanizing station, it is not easy to change the layout according to variations of the kinds of tires as well as the production amounts for the respective kinds, so that the system in the prior art lacks flexibility and becomes high in cost.